Field of the Disclosure
The present disclosure, for example, relates to wireless communication systems, and more particularly to communicating control information related to communications using an enhanced component carrier (eCC).
Description of Related Art
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
A wireless communication network may include a number of base stations that can support communication for a number of mobile devices, otherwise known as user equipments (UEs). Each base station may simultaneously supporting communication for multiple UEs. A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station). The UE may communicate with a base station via downlink (DL) and uplink (UL) transmissions. The DL (or forward link) refers to the communication link from the base station to the mobile device, and the UL (or reverse link) refers to the communication link from the mobile device to the base station.
The wireless communication networks including the base stations and mobile devices may support operation on multiple carriers which may be called carrier aggregation. Carrier aggregation may be used to increase throughput between a base station supporting multiple component carriers and a mobile device, and mobile devices may be configured to communicate using multiple component carriers associated with multiple base stations. Other techniques for increasing throughput using multiple carriers may be used where base stations performing joint operations have non-ideal backhaul (e.g., dual-connectivity, etc.). Multiple access technologies may use Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD) to provide UL and DL communications over one or more carriers.
In some instances of carrier aggregation, control information may be exchanged between nodes. However, sending control information on a secondary component carrier on an unlicensed or shared band may be inefficient due to the transmitting node needing to obtain media access. Sending control information on an unlicensed or shared band may also be inefficient because it could cause other nodes to back-off when the transmitting device is only sending a short burst of information. Further, the unlicensed or shared medium may not be available at particular times for providing feedback. For example, collisions may occur on the medium when providing feedback or the medium may be preempted by a higher priority operator. Therefore, providing reliable feedback for secondary carriers using unlicensed or shared spectrum provides challenges.